Custom control with invalid property generates no error

Question

for examle

<app:CustomDropDown ID="test" runat="server" InvalidProperty="SOMETHING" />

This does not generate an error. Sometimes i spend hours trying to figure out why my custom controls are displaying no data. Most of the time it turns out they are using and old non existing property and yet no error is generated on execution.

What could cause this?

Answer 1

You're not getting an error because, technically, there's nothing wrong with the markup. ASP.NET will pass any un-recognized attributes through to the page.

This can be useful if you want to use some non-standard attributes to store extra data for some reason and then access it later through the DOM.